Proceedings of The Physiological Society

Obesity (2014) Proc Physiol Soc 32, PC027

Poster Communications

The impact of high energy intake during early postnatal life on gene regulators for thermogenesis, adipogenesis and metabolism in the sternal and subcutaneous adipose tissue depots of sheep

M. Birtwistle1, P. Khanal2, A. H. Kongsted2, M. O. Nielsen2, H. Budge1, M. E. Symonds1

1. Early Life Research Unit, Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, United Kingdom. 2. Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Background and aims - The early life nutritional environment affects adipose tissue growth and susceptibility to later obesity and related adverse health (1). Using sheep as a model, we examined the effects of excess energy intake in early postnatal life on the growth and development of sternal and subcutaneous adipose tissue. We hypothesised that it would increase the amount of adipose tissue and that the expression of genes associated with thermogenesis, adipogenesis and metabolism would be modified.Materials and methods - As previously described (2), the offspring of twin-bearing sheep were separated from their mothers at 3 days of age and allocated to one of two dietary groups. The control (C) group was fed milk replacer for 8 weeks and green hay from 14 days of age. The high-carbohydrate high-fat (HCHF) group was fed a 1:1 mixture of milk replacer and cream, plus maize from 14 days of age. At age 6 months, 26 offspring (C: n=13; HCHF: n=13) were humanely euthanased and the sternal and subcutaneous (above the longissimus dorsi muscle) adipose tissue depots were excised. The relative expression of genes of interest was assessed by qPCR, using a two-tailed t-test or Mann-Whitney U-test to determine statistical significance.Results - At 6 months of age, animals on the HCHF diet were heavier (C: 36.1 ± 0.8 kg; HCHF: 42.3 ± 2.6 kg; p<0.05) and possessed more sternal (C: 1.0 ± 0.1 g/kg; HCHF: 4.0 ± 0.2 g/kg; p<0.001) and subcutaneous (C: 1.4 ± 0.1 g/kg; HCHF: 7.2 ± 0.5 g/kg; p<0.001) adipose tissue relative to body weight. There was no detectable expression of genes involved in thermogenesis. A number of genes associated with adipogenesis and metabolism were downregulated in the HCHF group in both tissues (Table 1). Leptin and RIP140 responded differently in the two tissues, being upregulated and downregulated respectively in the HCHF group in subcutaneous (but not sternal) adipose tissue.Conclusions - Excess energy intake during early postnatal life promotes adiposity and suppresses the expression of genes associated with adipogenesis and metabolism. Conversely, it enhances leptin expression in subcutaneous fat, which may contribute to reduced leptin sensitivity with age.

Where applicable, experiments conform with Society ethical requirements